The present invention relates to method of making a molded track for use with a snowmobile which is equipped with a suspension system having slide rails bearing on the inner face of the lower run of the track.
Snowmobile tracks are usually provided with a series of sheet metal clips located at spaced intervals in transversely separated longitudinal rows (usually two) of openings and so positioned as to engage, in slide bearing contact, the underside of slide rails forming part of the snowmobile suspension system. In most cases, these clips include a pair of spaced wings that are fixed to the belt by forcingly wrapping them around the rubber material in which is embedded a transverse reinforcing rod; an example of such track is illustrated in applicant""s Canadian patent no. 2,182,845 issued Mar. 30, 1999. These clips may or may not be located at each opening of the track; in other words, these metal clips may be present adjacent each opening while, in other cases, they may be provided at every third or fourth opening (an example of such track is described in applicant""s U.S. Pat. No. 5,722,745 issued Mar. 3, 1998). In some tracks, the guide clips are provided with upwardly projecting lug portions which are adapted to contact the side of the slide rails and prevent the track guide clips from moving laterally.
An example of such track for use in a snowmobile may be found described in U.S. Pat. No. 5,174,638 issued Dec. 29, 1992 to Tokue et al. Such tracks, as well as all other tracks, are manufactured through a series of known assembling steps and, once assembled, the rubber is vulcanized and cured to form a molded track. Therefore, each track is removed from its mold press and conveyed to a separate station where clips are individually clamped at predetermined locations along the track.
It is evident that this last separate step is an additional time consuming and costly operation as it requires special training and manpower.
It is an object of the present invention to obviate to the above problem associated with the presently method of manufacturing a snowmobile track by integrating these clips as a step prior to the presently known assembling steps of the various components forming the track and prior to the vulcanizing and curing steps.
Therefore, the present invention relates to a method of making a track for a snowmobile of the type having a suspension system equipped with slide rails, which comprises:
preparing a mold press consisting of a stationary inner mold and a movable outer mold; the inner part having one or more rows of peripherally spaced recesses having a predetermined shape;
inserting, in the recesses, a series of slide bearing elements; each element including a first generally flat portion having opposite inner and outer faces and having a shape corresponding to the shape of the recesses so that the elements may be inserted therein;
laying one or more layers of rubber and fabrics on the inner mold; and
vulcanizing the rubber to form a molded track whereby the elements are integrally formed with the molded track with the outer face of the flat portion of each element being exposed so that it is frictionally contacted by the slide rail during use of the snowmobile.
The present invention may be adapted to various constructions of snowmobile tracks including those which do not have openings (the track is driven by drive sprockets engaging lugs integrally formed to the inner surface of the track), tracks which require clips at a given number of opening intervals as well as tracks which require clips at every opening of the track.
Furthermore, this method applies also to tracks which are equipped with or without transverse reinforcing rods embedded in the rubber material of the tracks.
In one form of the invention, the recesses of the inner mold are equipped with magnets so as to hold these elements as they are mounted to the inner mold.
The present invention therefore avoids the presently known clipping step after the vulcanized track is cured.
In the present application, the word xe2x80x9cclipxe2x80x9d has been replaced by slide bearing elements. Indeed, once the formed track is removed from the mold press, there is no clipping procedure performed as the metallic elements are already integral with the track.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that this detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.